Is there support for forwarding to backends when clients are sending ALPN? I would like to use the stream module if possible. The following nginx config works successfully with a Go client but not with the Ruby client. This is similar to the problem with AWS ELB https://github.com/grpc/grpc/issues/18710


stream {
upstream stream_backend_1 {
server mygrpcservice:8080;
}
server {
listen 443 ssl;
proxy_pass stream_backend_1;
ssl_certificate /etc/ssl/test_cert.pem;
ssl_certificate_key /etc/ssl/test_key.pem;
ssl_preread on;
}
}

With preread on and nginx-debug I got the following in the logs and so the client is sending ALPN data
2019/12/15 03:21:12 [debug] 12#12: *1 ssl preread: ALPN protocols "grpc-exp"
2019/12/15 03:21:12 [debug] 12#12: *1 ssl preread: ALPN protocols "grpc-exp,h2"

but the Handshake fails in the grpc library because Server does not set the negotiated ALPN??
D1214 23:00:44.714269000 123145438679040 security_handshaker.cc:186] Security handshake failed: {"created":"@1576393244.714255000","description":"Cannot check peer: missing selected ALPN property.","file":"src/core/lib/security/security_connector/ssl_utils.cc","file_line":118}


Also fails with openssl

$ openssl s_client -connect test00.net:443 -alpn h2 | grep alpn
verify return:1
No ALPN negotiated

-s